Rivera was the defensive coordinator under Smith with the Chicago Bears, and Smith didn’t retain Rivera after the Bears went to the Super Bowl, despite Chicago having a top-five defense.

More than seven years later, neither coach wants to talk much about it.

“I’ve moved on from it,” Rivera said Friday. “To me, it’s a moot point, and it’s been a moot point for whatever the time frame is. It happens every year – coaches are moving on and getting other jobs. You go about it. If you sit there and dwell on it you’re going to do nothing but ruin yourself and, to me, he made a decision that I understood.”

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Rivera said “to a degree” the move was about a philosophical difference between the coaches. Plus, Smith wanted to work with Bob Babich, who replaced Rivera as defensive coordinator.

“I think first off, I try not to live in the past; it is about the future,” Smith said on a teleconference with reporters. “Ron Rivera is a friend and I enjoyed my time we worked together back then and I’m excited about competing against his team this week.”

Rivera said he understands the business side of it because he’s had to fire coaches before. In 2012, his second season as the Panthers coach, Rivera fired special teams coach Brian Murphy during the season. After the season he released receivers coach Fred Graves, running backs coach John Settle and linebackers coach Warren Belin.

Smith has called the decision to not retain Rivera business and not personal. Rivera said he doesn’t harbor any ill will toward Smith, and he sent him a congratulatory text after the Buccaneers hired Smith in January.

Rivera hasn’t had success against his old boss, though. He’s 0-2 against Smith, including a 34-29 loss in 2011 and a 23-22 loss in 2012.

Smith’s defensive coordinator, Leslie Frazier, is one of Rivera’s best friends inside or outside of football. Rivera said he hasn’t talked to Frazier but once in the past two weeks, and that was to make sure Bucs offensive coordinator Jeff Tedford would be OK after Tampa Bay announced he had an undisclosed illness.

There’s been some gamesmanship going on this week between Rivera and Smith. On Thursday, Rivera was coy about how much work Cam Newton did at practice. Smith has been equally evasive about offensive play-calling.

Splitting time: There are at least two starting positions for the Panthers still in the air going into Sunday.

Rivera said he and the staff are still deciding who will start at strongside linebacker and right guard.

Chase Blackburn and A.J. Klein are battling for the starting linebacker position beside Luke Kuechly and Thomas Davis. Fernando Velasco has challenged rookie Trai Turner for the starting right guard position between Ryan Kalil and Nate Chandler.

Rivera expects both pairs to share about equal reps Sunday.

“The thing about Trai that we have to be careful of is this is the first week of work he’s had in the last 2 1/2 and that’s a concern from the conditioning aspect,” said Rivera of Turner’s groin injury. “You don’t want to throw him out there and have a relapse or lose him for the next three or four weeks. We’re going to be smart.”

Rookie cornerback Bene Benwikere won the starting nickel job over Charles Godfrey, Rivera said. Godfrey will likely see time at strong safety to spell Roman Harper, who has practiced two weeks after missing more than three weeks with turf toe.

Jefferson suspended: Panthers tight end D.C. Jefferson, who is on injured reserve, has been suspended for four games for violating the league’s substance abuse policy, an NFL spokesman said.

Jefferson was waived/injured with a toe injury Aug. 26 during the first round of cuts, went unclaimed on waivers and reverted to the Panthers’ IR the following day.

Jefferson is the second Panthers’ player to be suspended for four games for violating the substance abuse policy. Reserve defensive end Frank Alexander began serving his suspension this week.

The Panthers signed Jefferson to the practice squad before their playoff game in January, and he was one of six tight ends in training camp. Jefferson appeared in four games with Arizona last season after the Cardinals drafted him in the seventh round out of Rutgers.

The Cardinals cut Jefferson in November after a DUI arrest. After Jefferson sideswiped another vehicle, his blood alcohol content was measured at .156, almost twice the legal limit, according to an ESPN.com report.

A Peppers reunion?: During the first half of Thursday’s Green Bay-Seattle game, an NBC color analyst said defensive end Julius Peppers signed with the Packers during the offseason after first talking with the Panthers, where Peppers played his first eight seasons and went to five Pro Bowls.

Peppers still has several friends in the organization and played for Panthers defensive line coach Eric Washington in Chicago. Peppers’ discussions with the Panthers were preliminary in nature, and there was never a formal contract offer, according to a league source.

Four days after the Bears released Peppers in a cost-cutting move in March, he signed a three-year, $26 million deal with the Packers.